Fuel for internal combustion engines

ABSTRACT

ADDITION OF GUANIDINE PETROLEUM SULFONATE TO HYDROCARBON FUELS RESULTS IN AN IMPROVED FUEL COMPOSITION HAVING REDUCED TENDENCY TO PRODUCE CARBON DEPOSITS WHEN UTILIZED IN THE OPERATION OF AN INTERNAL COMBUSTION ENGINE.

United States U.S. Cl. 44-74 6 Claims ABSTRACT OF THE DISCLOSURE Addition of guanidine petroleum sulfonate to hydrocarbon fuels results in an improved fuel composition having reduced tendency to produce carbon deposits when utilized in the operation of an internal combustion engine.

BACKGROUND OF THE INVENTION The increased concern over air pollution has resulted in equipping current model passenger cars with positive crankcase ventilation systems. These systems route the crankcase blowby gases through the intake system of the engine. Although these engine modifications reduce the amount of unburned hydrocarbons emitted to the atmosphere, they aggravate the accumulation of deposits in the carburetor around the throttle blade and ports adjacent to the throttle blade. When such deposits build up they upset the engine idle and can cause engine stalling, thereby requiring frequent carburetor adjustments.

There has thus developed a need for a motor fuel composition having a reduced deposit forming tendency in light of the widespread adoption of positive crankcase ventilation and the increased stop-and-go driving in high density traffic areas.

THE INVENTION It is an object of the present invention to provide an improved fuel composition for internal combustion engines.

It is a further object of the present invention to provide a fuel composition which avoids or substantially reduces deposits in the operation of an internal combustion engine.

Other aspects, objects, and the several advantages of this invention will be apparent from the following specification and claims.

We have now discovered that hydrocarbon fuels containing small quantities of a guanidine petroleum sulfonate have improved and much desired qualities as fuels for internal combustion engines. The fuels of this invention are useful in the same manner as the hydrocarbon fuels from which they are prepared. However, in comparison therewith the engines operated on fuels containing the guanidine petroleum sulfonate additive may be operated over longer periods of time with little, if any, deposits of carbon or tarry matter on the fuel intake surfaces of the engine and on the surfaces adjacent thereto.

Accordingly, our invention comprises the novel fuels for internal combustion engines hereinafter described and the use of these fuels for the operation of such engines.

The novel fuels of this invention comprise a hydrocarbon fuel having a small amount of a guanidine petroleum sulfonate therein.

The sulfonates can be added to any normally liquid hydrocarbon fuel such as light or heavy fuel oils, gasoline, or kerosene. Preferably, the said sulfonates are added to liquid hydrocarbon motor fuels comprised of components such as distillates of petroleum fractions, distillates of catalytic cracking products, distillates of reforming products, distillates of alkylates, distillates of alkylation processes, distillates of polymerization processe, and the like having a boiling point of not higher than 450 F., optionally volatilized with butane, pentanes, and the like;

atent ice and optionally containing tetraethyl lead and other additives known to the art. These fuels may also contain any of the usual aids and distinguishing constituents such as coloring matter, lubricants, antiknock agents, etc. The sulfonate content of the fuel may be varied over a relatively wide range, but in all cases it represents but a minor portion of the total fuel composition. Ordinarily the guanidine petroleum sulfonate additive is employed In a range of 15 to 30 pounds per 1000 barrels of fuel. However, up to 200 pounds of sulfonate per 1000 barrels of the hydrocarbon fuel can be added to form the improved fuel compositions of this invention.

Guanidine petroleum sulfonate additive as used in the present invention can be produced by any method known to the art and as such the method for the production of the additive is not to be construed as a limitation to the scope of the invention. The term guanidine salts as used herein is intended to include not only salts formed with the guanidine base per se; but, in addition, other derivatives of guanidine can be used. Thus, compounds useful in forming additives of the present invention are those of the formula wherein R is hydrogen or an alkyl, aryl, or cycloalkyl group containing from 1 to 6 carbon atoms per R group.

Guanidine salts of petroleum sulfonic acids can be formed by the neutralization of petroleum sulfonic acid with guanidine. I Although any sulfonated petroleum stock can be used n the formation of the guanidine salts of this invention, it is preferred that the petroleum stock be a deasphalted and solvent-refined petroleum bright stock containing at least 40 carbon atoms per molecule.

Such petroleum sulfonated base stocks are selected from the sulfonated derivative of viscous or bright stock fractrons of petroleum. One preferred base stock is the deasphalted and solvent-refined petroleum fraction having a viscosiy range between about and 700 SUS at 210 F. Another preferred sulfonation stock is propane fractionated-solvent extracted and dewaxed Mid-Continent oil of about 200 to 230 SUS at 210 F. having a viscosity index of about to or higher.

The following examples will further illustrate the invention but should not be construed as a limitation thereto.

EXAMPLE I Topped Mid-Continent petroleum is distilled to produce two separate distillates corresponding to SAE 10 and 20 raw base stocks. The final distillation kettle product or vacuum reduced crude is then subjected to a two-step solvent extraction employing liquid propane as the selective solvent. The propane extract of the first step contains oil of an average viscosity of about SUS at 210 F. (SAE 50 base stock) and the propane extract of the second step contains oil of an average viscosity of about 220 SUS at 210 F. (SAE 250- base stock). The raw SAE 250 base stock is recovered from the total extract of the second extraction step and then subjected to solvent extraction employing phenol as the selective solvent and to propane solvent dewaxing to produce a highly paraffinic raffinate comprising a lubricating oil stock having the following properties:

Viscosity, SUS at 100 F 5313 Viscosity, SUS at 210 F 223.3 Viscosity index 89 Gravity, API at 60 F 24 Average molecular wt 730 A solution of 1,000 g. of the lubricating oil stock described above dissolved in liquid ethylene chloride is slowly mixed with a solution of 176 g. of sulfur trioxide also dissolved in liquid ethylene chloride at a temperature maintained within the limits of 75-l15 F., at atmospheric pressure, under which conditions reaction of sulfur trioxide and the lubricating oil begin almost immediately to produce petroleum snlfonic acid. Reaction is completed shortly after admixing of the reactants is terminated. The ethylene chloride is stripped, and the resulting petroleum sulfonic acid product, hereinafter referred to as acid oil, is employed as follows.

Guinidine petroleum sulfonate suitable to be employed according to the process of this invention is then prepared by the following procedures.

(A) Use of formamide as solvent To a stirred mixture of 75 g. of guanidine carbonate in 2 liters of formamide heated to about 50 C. was added over a one-half hour period, 1 liter of an acid oil (such as prepared as above). Evolution of CO began after about a 5-minute induction period. The mixture was stirred at 50 to 60 C. for about 3 hours, or until the mix ture gave a pH reading of 9.0 or higher. pH readings were obtained in a solvent comprised of equal parts of isopropyl alcohol and toluene with a trace of water present. Stirring was stopped, the solution was diluted with an equal volume of naphtha, and the phases were allowed to separate. The top layer comprised of the hydrocarbon phase containing the guanidine petroleum sulfonate was decanted and stripped of solvent at 380 F. at a pressure of millimeters of mercury with a stream of inert gas to give the finished product, a guanidine petroleum sulfonate of the type suitable to be employed according to the process of this invention.

(B) Use of water solvent To a stirred solution of 50 g. of guanidine carbonate in 3 liters of water heated to 50 C. was added over a twohour period 500 ml. of acid oil. The mixture was stirred at 50 C. for 12 hours. Water was stripped at 200 C. in vacuum with a rapid stream of natural gas. The remaining residue was than diluted with 3 volumes of Stoddard solvent and filtered in vacuo through a Celite (diatomaceous earth) filter cake. The filtrate was stripped of solvent at 380 F. at 20 millimeters of mercury pressure with a stream of natural gas to yield a finished guanidine petroleum sulfonate product of the type suitable for use according to the process of this invention.

(C) By ammonium exchange Aqueous ammonium hydroxide solution (28-30% NH was added to a mixture of 300 g. of acid oil and 700 m1. of n-heptane until the mixture became basic. The resulting mixture was filtered in vacuo through a Celite filter cake to remove the insoluble inorganic salts. A slight excess over the equivalent amount of guanidine carbonate was added to the filtrate, and the mixture was heated to reflux temperature. The ammonium petroleum sulfonate underwent exchange of ammonium ion for guanidine ion to give the guanidine petroleum sulfonate and ammonium carbonate. The ammonium carbonate underwent decomposition to give ammonia, carbon dioxide, and water; all of which escaped from the refluxing mixture. The reflux conditions were continued until ammonia vapors could no longer be detected. The resultant mixture was stripped of volatiles to leave the finished product, a guanidine petroleum sulfonate suitable for employment according to the process of this invention.

The above ammonia process is particularly preferred as a means of preparing a guanidine petroleum sulfonate suitable for employment according to the process of the instant invention.

4 EXAMPLE 1r Suflicient guanidine petroleum sulfonate formed by neutralization of K.C. acid oil (KC 250 stock) was added to a commercial gasoline (Phillips 66) in an amount to give a concentration of 20 pounds of guanidine petroleum sulfonate per 1000 barrels of commercial grade gasoline.

The resulting guanidine petroleum sulfonate-gasoline composition was employed in the operation of a Falcon engine (from a Ford Falcon motor car) equipped with dual carburetors leading to a common fuel and air intake to the manifold. Each carburetor was provided with a separate fuel supply and was equipped with a removable sleeve in the carburetor throat area. The carburetors were identical. To accelerate deposit formation crankcase fumes were charged to the common air supply for the carburetors. This arrangement permitted comparison of fuels for antideposit activity concurrently under identical conditions.

According to the test cycles employed, the engine was operated at 700 rpm. until its power output decreased by forty percent from the accumulation of carburetor deposits. Following power reduction, the carburetor deposits were Washed with fuel by three consecutive 1.5 minute operating periods at 2000 rpm. This high speed operation which was employed to restore most of the original power output of the engine was repeated whenever further operation at 700 rpm. resulted in loss of forty percent of power. After six hours operation under these conditions the throttle was opened to operate at 2000 rpm. for 15 minutes. Thereafter each sleeve located in each respective carburetor throat area was removed and the deposit formation thereon measured.

A similar series of runs were carried out using ammonium petroleum sulfonate and calcium petroleum sulfonate formed from the same KC 250 petroleum base stock.

As is readily discernible by those skilled in the art, the difference in weight of carburetor deposits between treated and untreated fuel is a measure of the antideposit activity of the antideposit additive employed in the treated fuel, e.g., the greater the excess of deposit weight effected by untreated fuel over that effected by treated fuel, the more effective is the antideposit additive.

For each additive, two runs were made wherein treated fuel was charged to one carburetor in one run and the other carburetor in the second run to cancel out any equipment bias. Results were obtained as are presented in the following table:

1 Average of runs (deposit from untreated-deposit from treated).

The above data clearly demonstrate that a significant reduction in carburetor deposits is achieved by use of the guanidine sulfonate and that use of guinidine petroleum sulfonate as an additive to the fuel results in a totally unexpected reduction in the deposit formation as compared with the results obtained by utilization of other known additives.

Reasonable variations and modifications of this invention can be made, or followed, in view of the foregoing disclosure, without departing from the spirit or scope thereof.

We claim:

1. A liquid hydrocarbon motor fuel for use in an internal combustion engine, said fuel containing 15 to 200 pounds of a guanidine petroleum sulfonate per 1000 barrels of said hydrocarbon fuel wherein said guanidine petroleum sulfonate is prepared by reaction of a sulfonated deasphalted, solvent-refined petroleum bright stock having at least 40 carbon atoms per molecule and a guanidine of the formula RlTI-H (|3=NH B.N-H

wherein -R is hydrogen or an alkyl, aryl, or cycloalkyl group containing 1 to 6 carbon atoms per R group.

2. A motor fuel composition according to claim 1 wherein said liquid hydrocarbon motor fuel is a fuel having a boiling point below 450 F.

3. A composition according to claim 1 wherein R is hydrogen and wherein said guanidine petroleum sulfonate is present in an amount in the range of 15 to 30 pounds per 1000 barrels of liquid hydrocarbon motor fuel.

4. In the operation of an internal combustion engine, the improvement which comprises supplying as a fuel to said engine a liquid hydrocarbon motor fuel containing 15 to 200 pounds of a guanidine petroleum sulfonate per 1000 barrels of fuel wherein said guanidine petroleum sulfonate is prepared by reaction of a sulfonated, deasphalted, solvent-refined petroleum bright stock having at least 40 carbon atoms per molecule and a guanidine of the formula References Cited UNITED STATES PATENTS 2,296,069 9/1942 Talbert m1 44-72X 3,317,291 5/1967 Marsh a a1. 44-72 FOREIGN PATENTS 546,875 10/1957 Canada 44-72 DANIEL E. WYMAN, Primary Examiner W. I. SHINE, Assistant Examiner US. Cl. X.R. 

